Thin film characterization by atomic force microscopy at ultrasonic frequencies

We present a technique in which atomic force microscopy at ultrasonic frequ encies is used to determine the thickness of thin films. In this technique, the resonance frequency of a flexural mode of an atomic force microscope c antilever is used to determine the tip-sample contact stiffness. This allow s the film thickness to be determined, provided that the tip and sample ela stic moduli and radii of curvature are known. We report experimental result s for thin metal and polymer films deposited on silicon substrates and comp are them with the predictions of a theoretical model. (C) 2000 American Ins titute of Physics. [S0003-6951(00)00114-5].